list_dir.c

   1 /*
   2  * User FTP Server,  Share folders over FTP without being root.
   3  * Copyright (C) 2008  Isaac Jurado
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License as published by the Free Software
   7  * Foundation; either version 2 of the License, or (at your option) any later
   8  * version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  18  */
  19
  20 #include "uftps.h"
  21 #include <sys/stat.h>
  22 #include <unistd.h>
  23 #include <dirent.h>
  24 #include <time.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27
  28 /* Month names */
  29 static const char const month[12][4] = {
  30         "Jan\0", "Feb\0", "Mar\0", "Apr\0", "May\0", "Jun\0", "Jul\0", "Aug\0",
  31         "Sep\0", "Oct\0", "Nov\0", "Dec\0"
  32 };
  33
  34
  35 /*
  36  * LIST and NLST commands implementation.  The boolean argument enables LIST
  37  * mode, otherwise NSLT listing is sent.
  38  *
  39  * To make Mozilla Firefox list the directory contents correctly, some research
  40  * work had to be done.  That concluded in:
  41  *
  42  *     http://cr.yp.to/ftp.html
  43  *
  44  * In particular:
  45  *
  46  *     http://cr.yp.to/ftp/list/binls.html
  47  *
  48  * Only files or subdirectories are shown, the rest of items (symlinks, named
  49  * pipes, sockets...) are ignored.  The following line is sent when a file is
  50  * found:
  51  *
  52  * -rw-r--r-- 1 ftp ftp       999 Mon  88 7777 filename
  53  *
  54  * In case of a subdirectory, the line is:
  55  *
  56  * drwxr-xr-x 1 ftp ftp       999 Mon  88 7777 dirname
  57  *
  58  * Where '999' is the item size, 'Mon  88 7777' is the month, day and year,
  59  * respectively, of the last modification date.  Some servers display the hour
  60  * and minute when the distance between current time and last modification time
  61  * is less than six months.  We don't do that as it is considered irrelevant.
  62  * To obtain a more precise value for the last modification time, let the client
  63  * send an MDTM command.
  64  *
  65  * Note that most clients will appreciate listings where all its items are
  66  * stat()-able.
  67  */
  68 void list_dir (int full_list)
  69 {
  70         int             len, l, e;
  71         DIR            *dir;
  72         struct dirent  *dentry;
  73         struct stat     s;
  74         struct tm       t;
  75         char            item[512];
  76
  77         /* Workaround for Konqueror and Nautilus */
  78         if (SS.arg != NULL && SS.arg[0] == '-')
  79                 SS.arg = NULL;
  80         len = expand_arg();
  81
  82         dir = opendir(SS.arg);
  83         if (dir == NULL)
  84         {
  85                 error("Opening directory '%s'", SS.arg);
  86                 reply_c("550 Could not open directory.\r\n");
  87                 return;
  88         }
  89
  90         /* Prepare the argument for the listing, see below */
  91         if (len > 3)
  92         {
  93                 SS.arg[len - 1] = '/';
  94                 len++;
  95         }
  96
  97         e = open_data_channel();
  98         if (e == -1)
  99         {
 100                 closedir(dir);
 101                 return;
 102         }
 103
 104         reply_c("150 Sending directory list.\r\n");
 105
 106         do {
 107                 dentry = readdir(dir);
 108                 if (dentry == NULL)
 109                         break;
 110
 111                 /*
 112                  * Due to the chroot emulation, each dentry needs to be
 113                  * prepended by the expanded argument (stored in the auxiliary
 114                  * buffer) after checking bounds.  Otherwise, the stat() call
 115                  * would fail.
 116                  */
 117                 l = strlen(dentry->d_name);
 118                 if (len + l >= LINE_SIZE)
 119                         fatal("Path overflow in LIST/NLST");
 120                 strcpy(&SS.arg[len - 1], dentry->d_name);
 121
 122                 debug("Stating %s", SS.arg);
 123                 e = lstat(SS.arg, &s);
 124                 if (e == -1 || (!S_ISDIR(s.st_mode) && !S_ISREG(s.st_mode)))
 125                 {
 126                         debug("Dentry %s skipped", SS.arg);
 127                         continue;
 128                 }
 129
 130                 if (full_list)
 131                 {
 132                         /* LIST */
 133                         gmtime_r(&(s.st_mtime), &t);
 134                         l = snprintf(item, 512,
 135                                      "%s 1 ftp ftp %13lld %s %3d %4d %s\r\n",
 136                                      (S_ISDIR(s.st_mode) ? "dr-xr-xr-x"
 137                                       : "-r--r--r--"), (long long) s.st_size,
 138                                      month[t.tm_mon], t.tm_mday, t.tm_year + 1900,
 139                                      dentry->d_name);
 140                 }
 141                 else
 142                 {
 143                         /* NLST */
 144                         l = snprintf(item, 512, "%s%s", dentry->d_name,
 145                                      (S_ISDIR(s.st_mode) ? "/\r\n" : "\r\n"));
 146                 }
 147
 148                 e = data_reply(item, l);
 149         } while (e == 0);
 150
 151         if (e == 0)
 152                 reply_c("226 Directory list sent.\r\n");
 153         else
 154                 reply_c("426 Connection closed, transfer aborted.\r\n");
 155
 156         closedir(dir);
 157         close(SS.data_sk);
 158         SS.data_sk = -1;
 159 }
 160